Electrical outlet plug



my EE, ma. H. THORIN 049,03

ELECTRICAL OUTLET PLUG Filed June 18, 19154 INVENTOR,

Patented July 28, 1936 UNITED STATES -This invention relates to improvements in elecl trical outlet plugs.

An object of my invention is to provide an outlet plug that may readily be locked into its socket, in order to prevent its being withdrawn when a comparatively slight pull is exerted upon an electrical cord, or cable, that is attached to the plug.

At the present time, when an extension cord is used for carrying a lamp, or other electrical device, at its outer end, for various uses, as for example, in making repairs on an automobile, thel plug is often withdrawn from its socket, upon'a slight pull, thus rendering the lamp, or other electrical device useless. Frequently, the extension cord is a long and comparatively heavy one, with the result it is dicult to make the plug remain in its socket, when in use.

Broadly stated, my improvements consist in providing one of the contact blades of the plug with a locking device, or attachment, whereby, when the plug is to be used and the attachment is moved into one position, the plug cannot be withdrawn from its socket, and, when the attachment is moved into its original position, the plug may be readily withdrawn in the usual way.

In one form of my invention, I form a tapered, angular recess in one blade of the plug and a member slidable in the recess for exerting a pressure on the blade and the adjacent wall of the plug.

In another form of my invention, I form one .blade of the plug with a channel-like structure, in which is placed a rotatable, flat-shaped member having teethlike, or serrations, on its opposite edges. Means are provided for rotating this flat-shaped member, whereby the blade of the plug will be rmlv retained in its socket; when it is turned back again, the plug is then free to be withdrawn.

Referring to' the drawing which forms a part of the specication, and in which:-

Fig. 1 is a verticalsectional view, showing the plug locked, or retained in place in the socket.

Fig. 2 is a detail, perspective view. of one of the blades of the plug removed from the plug and showing the angular and tapered groove therein.

Fig. 3 is a detail, perspective view of the slidable plug member that is located in the angular and tapered groove of the plug.

Fig. 4 is a transverse, sectional view of the blade on the line -4-4 of Fig. 2.

Fig. 5 is a vertical, sectional view of a. modification through the socket and plug with the plug locked in place.

Fig. 6 is a perspective view of one of the blades of 'the modified construction of the plug, removed .from the plug. y v

Fig. 7 is a detail, perspective viewof thev at,

-locking member formed withv the ser-rations on its opposite edges, and

Fig. 8 is a sectional view on the line 8 8 of Fig. 6, showing'the serrations.

Referring to the drawing in detail:-

- I indicates the socket portion as a whole, hav ing the usual spring contact terminals 2 and 3, 1o located in the recesses 4 and 5. 6 indicates the removable plug member to which is secured the contact blades 1 and 8 and formed with the openings 8'. One of the blades, as 8, is formed with the V-shaped and longitudinally tapered groove, 15 or recess, 9, having the stop, or shouldered, upper end portion I I). The upper end portion of the blade 8 is formed with an opening II in which is slidably locatedthe rod member I2 on lthe lower end of which is the enlargement, or block 20 I3, having the inclined faces I4 and I5, the angle of which corresponds with the angle of inclina-'- tion of the opposite surfaces I6 and I1 of the groove, or recess 9. The face, or surface I8, of

Y the block I3, engages the vertical wall I 9 of the 2g socket I, as shown, when the block I3 is moved downward by pressure on the knob 2U at the upper end of the rod I2, and against the tension of the expansion ,spring 2l. When in this'position, the plug 6 is rmly and frictionally retained in the 30 socket, by reason of the tapered groove construction 9. When the block I3 is drawn upward against the shoulder I0, the blade 3 is f ree and the plug 6 may be withdrawn in the usual manner. 'I'he spring 2I will now retain it in this 35 position.

Referring to the construction, shown in Figs. 5, 6, '7, and 8; 22 and 23 indicate the two contact blades of the plug 6. The-blade 23 is formed with the ear portions 24 and 25, and the opening 40 26. located in the space 21' between the ear portions is a flatblade member 21, having the oppositely located projections 28. 'Ihe rod portion 29 is located in the opening 26 of the blade 23, and inthe opening 8 of the plug 6, as shown. 29 indicates a spring stop for engaging one of the shoulders 30, for retaining the blade member 21 in its locking position, shown in Fig. 5, when turned through an arc of 90. In this position, the teeth 28 engage the blade 23 and the surface wall I 9, whereby the plug 6 is prevented from being withdrawn, when the blade 21 is turned, so as to lie within the space 21', the teeth 28 will not engage the wall I9, nor the blade 23. The

`when assembled, slidable means in the plug inl plugB can now be withdrawn from the socket l in the usual manner.

From this decription, it will be seen that I have provided a very inexpensive and simple means for retaining a plug in its socket and which means will permit the plug to be withdrawn, in`

.means, whereby the plug is frictionally retained against easy removal from its socket, and whereby relative lateral motion of said plug blade andwedge means is prevented.

2. A plug and socket construction comprising,

, in combination with a contact blade of the plug, 25,

said blade having a tapered and V-shaped groove in cross section formed therein, a wedge-shaped block slidably located in the said groove, a rod connected to the block and extending through and above the plug cap, a knob on the upper end ofthe rod, spring means on the rod between the knob and the top of the cap for retaining the wedge-shaped block in its inoperative elevated position in the-upper end of the said groove for removing lateral pressure on the blade of the plug by thel said rod portion which extends through the opening in the plug part and above the same for operating the wedge-shaped block.-

3. In an electric plug and -socket construction having engageable contact and blade members engagement with a blade of the plug and a. wall of thesocket for frictionally retaining the plug against removal, said means comprising a grooved portion in the said blade of the plug which groove is tapered in the direction ofthe 5 movement of the slidable means in the plug and V-shaped in cross section, the slidable member which is tapered and V-shaped in cross section is located in the said grooved portion for forcibly engaging the said blade and the said wall of the 1 0 socket.

4. In combination in an electric socket and its removable plug, means for retaining the plug connected to the socket in order to vprevent its removal upon a slight pull, said means coml5 prising a tapered groove in a blade of the plug, a slidable memberin the said groove and adjacent a wall of the socket in-which a contact is located, the groove being tapered from the'u'pper end portion of the blade and downward towards 20 its lower end, whereby when the slidable mem- .ber in the groove is moved downward in the groove in the blade and against said wall of the socket, the plug and its blade will be frictionally retained against removal from the socket mem- 2q;

ber, as described.

5. In combination in an electric socket and its plug in which the contact terminals mutually contact when assembled, slidable means associated with a blade of the plug; and extending 30.

through an opening in the blade and an openingI in the plug to its outer end surface, a knob on the slidable means, the blade having a V-shaped-and tapered groove with which the slidable means engages, a stop shoulder at one end of said 35.' groove, a spring for retaining the slidable member against the stop, said spring being located between the knob and the outer end of the Plug. y HARRY THORIN. 

